I made some progress this weekend. Here's the printed out mag well.
The printed part came out alright, though it definitely needs some adjustments. The space for the magazine's directional tab is too small and the holes for the bolts too big. It will do just fine for the first round though.
I've also gotten the air cylinder, QEV, and DCV in the mail. Here's the basic setup for the first test.
I need to make the inside of the chamber (the PVC tee joint) as laid out in this thread. I also need to machine the ram rod that I just got in the mail today. It's 9/16" Derlin rod that will go on the end of the air cylinder. Hopefully I'll have a video demonstration of the whole this working next weekend.